References: Pgs 25-26, 169-170, 1070-1071

Purpose: (Listen to pre-lab discussions and supply a complete purpose statement for this lab. In other words, why are we doing this lab?) ______

______

Pre-Lab Questions: Answer on a separate sheet of binder paper.

1.Give the complete name for the microscope used in Part 1 of this lab.

2.Using the diagram on the bottom of pg 1070, label the designated parts of the microscope drawing provided.

3.Total magnification:

Using directions given on pg 1070 calculate the total magnification for a microscope with the standard eyepiece and a low power objective lens (10x)? and a high power objective lens (43x)? And a scanning objective lens (4x) (this lens is not available on all microscopes).

4.Care of the Microscope

Since the microscope works on the principle of visible light passing through transparent objects and lenses, special care is necessary to keep various parts of the microscope and slides used with them clean at all times. Special tissues are used to clean the slides as well as the lenses (#12 pg 1071)

A. Slide tissue – a course tissue used for the least expensive glass parts of the microscope as well as glass slides.

B. Lens tissue – a fine tissue and soft enough to clean the most delicate parts of the microscope.

Make a list of the following items, Objective Lenses, Slides, Coverslips, Condenser (=Light source), Eyepiece, and Stage, and identify the type of tissue that should be used with each item.

5.Supply the missing words to this sentence. Always carry the microscope with __?__ hands, one hand under the ___?___ and the other grasping the ___?___. (#1 pg 1070)

6.List 3 things that should be done when you have finished using the microscope. (#12 pg 1071)

7.Wet mount Preparation

Study Figure on pg 1071. Note the proper technique for applying a coverslip to the surface of a slide. Why should the coverslip be lowered at an angle onto the slide?

8.Setting up the Microscope

Provide the correct numerical sequence (ex. 5,3,1,…) that corresponds to proper sequence to follow when viewing a slide under High Power magnification.

1. Center the object being viewed under Low Power.

2. Readjust the light adjuster (diaphragm) to get the best light.

3. Find the object under the Lower Power available first.

4. Turn the High Power objective into viewing position, NOT changing the focus.

5. Focus with coarse adjustment, and adjust the light adjuster for the best lighting possible.

6. Sharpen the focus with fine adjustment only. Never use coarse adjustment with High Power objective lens.

Procedure
Part 1 – Practice in the use of the microscope

1.Cut out the smallest CAPITAL letters, "H", "A", and "F" from the paper provided.

2.Prepare ONE wet mount slide with all 3 letters.

3.Place the slide on the stage (no water on the stage…ask your self… what kind of paper do you use to wipe up any excess water?) with the letter "H" over the hole of the stage.

4.Use the lowest power available and examine the newspaper. Move the "H" until it is in the field of vision. Sketch exactly what you see in the space provided under the section marked DATA.

5.Now, move the "A" into the field of vision. Be sure that on the stage the "A" would read correctly. Peak to see if the "A" is right side up or upside down on the stage, correct the "A" if it is not right side up+. Now draw the "A" in the space provided. Now ask yourself…"What happened to the position of the "A"?".

6.Do the same with the letter "F". Again be sure it reads properly on the stage. Sketch it accurately. Now ask yourself…"What happened to the "F"?".

Teacher checkpoint. Before going on, show the teacher your beautiful sketches of H, A, and F.

7.Obtain a prepared (=Permanent) slide of the letter "e".

8.In the space provided under DATA, sketch the letter "e" as you see it with the naked eye. Show as much detail as you can.

9.Place the letter "e" slide on the stage and focus its image under low power magnification. Be sure the image is in the field of vision. Sketch this "e" accurately.

Summary

What a microscope does to the image is…

it ______

it turns it ______

and ______

10.Assuming the "e" is still focused and in the field of vision at 100x, rotate the nosepiece and set the High Power objective lens. The High Power lens will nearly touch the slide but should really require little adjustment and if needed ONLY USE the fine adjustment knob. Go back to your original sketch of the "e" and using a RED pencil, outline the part of the "e" which remained visible under 430x.

DATA

11.Return to the letter "e" in Low Power viewing. While looking through the microscope, move the slide GENTLY up or away from yourself. Ask yourself "Which way does the image appear to move?". Now move the slide to the left, ask yourself "Which way does the image move?". Therefore, if a microorganism appears to be moving into the upper right of the field of vision, which way should you move the slide in order to get the "critter" back into the field of vision? ______

12.Which power seems to be more sensitive to depth of field?______
From what you have observed would it be more difficult to focus on a diving or rising microorganism on Low Power or High Power magnification? ______

Summary

As the power of microscopic magnification increases, the….

Field of vision ______

Depth of field ______

Amount of light passing through the lens system ______

Discussion Questions

1.One advantage of using Low Power (100x) is?

2.One disadvantage of using Low Power is?

3.One advantage of using High Power (430x) is?

4.One disadvantage of using High Power is?

Using either 100x (Low Power) or 430x (High Power), match them to the following statements

5a.easier and faster to locate microorganisms

5b.more details can be seen with this power

5c.microorganisms would appear to be moving faster on this power

5d.easier to lose microorganisms while viewing them

5e.can see more of the microorganism

Conclusions:

In a paragraph write a conclusion that answers the following:

  • Summarize the new information or techniques you have learned from completing this lab. Include how to use/ handle a microscope.
  • What happens to the image when you look at it through a microscope?

______